• Title/Summary/Keyword: Nano %24TiO_2%24

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The Effect of Nano-scale Zn-$TiO_2$ and Pure $TiO_2$ Particles were Prepared using a Hydrothermal Method on Zebrafish Embryogenesis (수열합성법으로 제조된 Zn-$TiO_2$ 나노입자와 $TiO_2$ 나노입자가 zebrafish 배발생에 미치는 영향)

  • Yeo, Min-Kyeong;Kim, Hyo-Eun
    • Environmental Analysis Health and Toxicology
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    • v.24 no.4
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    • pp.333-339
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    • 2009
  • In this study, we investigated the biological toxicity of nano-scale Zn (0.1, 0.5, and 1 mol%)-doped $TiO_2$ and pure $TiO_2$ nanoparticles using zebrafish embryogenesis as our model organism. Zn-doped $TiO_2$ nanoparticles were prepared using a conventional hydrothermal method for the insertion of zinc into the $TiO_2$ framework. The characters of Zn-doped $TiO_2$ (0.1%, 0.5%, 1%Zn) and pure $TiO_2$ were about 7~8 nm. These sizes were smaller than 100~200 nm of $TiO_2$ was prepared using the sol-gel method. Particularly, in this study, we found no significant biological toxicity in the hatching rate and abnormal rate under expose pure $TiO_2$ and Zn-doped $TiO_2$ nanoparticles were prepared using a conventional hydrothermal method of zebrafish. It was different from the biological damage under $TiO_2$ nanoparticles were prepared using sol-gel method. We assessed that the damage was not linked to the particle's nanometer size, but rather due to the prepare method. Moreover, $TiO_2$ nanoparticles were prepared using a hydrothermal method were not shown to cause cytotoxic effects, like apoptosis and necrosis, that are the major markers of toxicity in organisms exposed to nanomaterials. Therefore, there is some relationship with biological toxicity of nanoparticles and the prepare method of nanometer size particles.

Effect of Nano Particles on Fertilized Egg of Crossostrea gigas (참굴(Crassostrea gigas) 수정란에 미치는 나노입자의 영향)

  • Lee, Byeong-Woo;Park, Chan-Il;Choi, Kwang-Soo;Kim, Mu-Chan
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.14 no.1
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    • pp.9-14
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    • 2008
  • A Nano particle is a small particle with at least one dimension less than 100 nm Nanoparticle is currently used in an area cf intense scientific research, due to a wide variety cf potential applications in biomedical, optical, and electronic fields. In order to know the biological effect of the nine Nano particles on fertilized egg of Crassostrea gigas experiments were performed Development rates of control (free Nano particles) C. gigas to a particular larval stage (D-shape) was 78%. Development rate of C gigas to a parcicular larval stage (D-shape) after 24 hours exposure to 0.05ppm of AGZ020, Nano silver, P-25 and SnO were 22%, 52%, 58% and 76%, respectively. However, all fertilized eggs were destructed within 8 hours afters exposure to 20ppm of respective particles. On the other hand, All fertilized eggs were not affected after 24 hours respective exposure to 0.05ppm of In, Sb, Sn, Zn, and Ag-$TiO_2$ particles. However, development rates of C. gigas after 24 hours exposure to 20ppm of In, Sb, Sn, Zn, Ag-$TiO_2$ were 57%, 60%, 50%, 65%, and 64% respectively.

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Effects of Sputtering Pressure on the Properties of BaTiO3 Films for High Energy Density Capacitors

  • Park, Sangshik
    • Korean Journal of Materials Research
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    • v.24 no.4
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    • pp.207-213
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    • 2014
  • Flexible $BaTiO_3$ films as dielectric materials for high energy density capacitors were deposited on polyethylene terephthalate (PET) substrates by r.f. magnetron sputtering. The growth behavior, microstructure and electrical properties of the flexible $BaTiO_3$ films were dependent on the sputtering pressure during sputtering. The RMS roughness and crystallite size of the $BaTiO_3$ increased with increasing sputtering pressure. All $BaTiO_3$ films had an amorphous structure, regardless of the sputtering pressures, due to the low PET substrate temperature. The composition of films showed an atomic ratio (Ba:Ti:O) of 0.9:1.1:3. The electrical properties of the $BaTiO_3$ films were affected by the microstructure and roughness. The $BaTiO_3$ films prepared at 100 mTorr exhibited a dielectric constant of ~80 at 1 kHz and a leakage current of $10^{-8}A$ at 400 kV/cm. Also, films showed polarization of $8{\mu}C/cm^2$ at 100 kV/cm and remnant polarization ($P_r$) of $2{\mu}C/cm^2$. This suggests that sputter deposited flexible $BaTiO_3$ films are a promising dielectric that can be used in high energy density capacitors owing to their high dielectric constant, low leakage current and stable preparation by sputtering.

Synthesis and Sintering of Nanostructured Mg4Al2Ti9O25 by High-Frequency Induction Heating and Its Mechanical Properties (고주파 유도 가열에 의한 나노구조 Mg4Al2Ti9O25 합성 및 소결과 기계적 성질)

  • Kang, Hyun-Su;Doh, Jung-Mann;Yoon, Jin-Kook;Shon, In-Jin
    • Korean Journal of Materials Research
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    • v.24 no.2
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    • pp.67-72
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    • 2014
  • Nanocrystalline materials have received much attention as advanced engineering materials with improved physical and mechanical properties, including high strength, high hardness, excellent ductility and toughness. In this study, nanopowders of $Al_2O_3$, MgO and $TiO_2$ were prepared as starting materials by high energy ball milling for the simultaneous synthesis and sintering of the nanostructured compound $Mg_4Al_2Ti_9O_{25}$ by high-frequency induction heating process. The highly dense nanostructured $Mg_4Al_2Ti_9O_{25}$ compound was produced within one minute by the simultaneous application of 80MPa pressure and induced current. The sintering behavior, grain size and mechanical properties of the $Mg_4Al_2Ti_9O_{25}$ compound were evaluated.

Development of A Material Flow Model for Predicting Nano-TiO2 Particles Removal Efficiency in a WWTP (하수처리장 내 나노 TiO2 입자 제거효율 예측을 위한 물질흐름모델 개발)

  • Ban, Min Jeong;Lee, Dong Hoon;Shin, Sangwook;Lee, Byung-Tae;Hwang, Yu Sik;Kim, Keugtae;Kang, Joo-Hyon
    • Journal of Wetlands Research
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    • v.24 no.4
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    • pp.345-353
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    • 2022
  • A wastewater treatment plant (WWTP) is a major gateway for the engineered nano-particles (ENPs) entering the water bodies. However existing studies have reported that many WWTPs exceed the No Observed Effective Concentration (NOEC) for ENPs in the effluent and thus they need to be designed or operated to more effectively control ENPs. Understanding and predicting ENPs behaviors in the unit and \the whole process of a WWTP should be the key first step to develop strategies for controlling ENPs using a WWTP. This study aims to provide a modeling tool for predicting behaviors and removal efficiencies of ENPs in a WWTP associated with process characteristics and major operating conditions. In the developed model, four unit processes for water treatment (primary clarifier, bioreactor, secondary clarifier, and tertiary treatment unit) were considered. Additionally the model simulates the sludge treatment system as a single process that integrates multiple unit processes including thickeners, digesters, and dewatering units. The simulated ENP was nano-sized TiO2, (nano-TiO2) assuming that its behavior in a WWTP is dominated by the attachment with suspendid solids (SS), while dissolution and transformation are insignificant. The attachment mechanism of nano-TiO2 to SS was incorporated into the model equations using the apparent solid-liquid partition coefficient (Kd) under the equilibrium assumption between solid and liquid phase, and a steady state condition of nano-TiO2 was assumed. Furthermore, an MS Excel-based user interface was developed to provide user-friendly environment for the nano-TiO2 removal efficiency calculations. Using the developed model, a preliminary simulation was conducted to examine how the solid retention time (SRT), a major operating variable affects the removal efficiency of nano-TiO2 particles in a WWTP.

Photo-degradation of Phenol and Toluene by Using the TiO2-coated Polyethylene Particles (TiO2가 코팅된 Polyethylene 입자를 이용한 페놀과 톨루엔의 광분해)

  • Kim, Dong-Joo;Choi, Sang-Keun;Cho, Jun-Hyung;Kim, Kyo-Seon
    • Journal of Industrial Technology
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    • v.24 no.B
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    • pp.133-138
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    • 2004
  • The photodegradation of phenol and toluene with the $TiO_2$-coated polyethylene (PE) particles were investigated in the slurry type photocatalytic reactor, changing the $TiO_2$ particle sizes, initial phenol and toluene concentrations, and the oxygen flow rate. The nano-sized $TiO_2$ photocatalyst particles were prepared by the diffusion flame reactor and they were coated onto PE particles by using the hybridization system for the efficient recollection of $TiO_2$-coated particles after photodegradation experiments. The degradation efficiencies of phenol and toluene with the $TiO_2$-coated PE particles were more than 90% after photodegradation of 80 minutes for most cases. The efficiencies of photodegradation with the $TiO_2$-coated PE particles were found to be lower than those by the pure $TiO_2$ particles by 50%, because of the decrease in specific surface area of $TiO_2$ particles in PE particles.

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Preparation and Characterization of Cerium Doped Titanium Dioxide Nano Powder for Photocatalyst

  • Ndinda, Euphracia;Park, Hyun;Kim, Kyung Nam
    • Korean Journal of Materials Research
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    • v.24 no.1
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    • pp.33-36
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    • 2014
  • This study was aimed at synthesizing and characterizing cerium-doped titania. Cerium-doped anatase titania powders were prepared by sol-gel process, with ammonium (IV) nitrate and titanium (IV) butoxide as the raw materials. The characteristics of pure $TiO_2$ and cerium-doped $TiO_2$ were investigated by XRD, TG/DTA, FE-SEM, and UV-vis spectroscopy. The results of this study show that anatase type of $TiO_2$ was obtained in as-prepared and calcined $TiO_2$ and Ce-$TiO_2$ powder. A DTA curve was also observed as the crystallization temperature decreased with increasing cerium contents. We found that the crystallite size of the obtained anatase particles decreased from 55 nm to 25 nm and the particle size decreased with increasing cerium contents. Moreover, UV-vis spectra showed that anatase titania powders with various cerium contents effectively extend the light absorption properties to the visible region.

The Synthesis of Eu3+ Doped with TiO2 Nano-Powder and Application as a Pesticide Sensor

  • Yao, Fei;Sun, Yang;Tan, Chunlei;Wei, Song;Zhang, Xiaojuan;Hu, Xiaoyun;Fan, Jun
    • Journal of the Korean Chemical Society
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    • v.55 no.6
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    • pp.932-935
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    • 2011
  • Using tetrabutyl titanate as precursor, $Eu^{3+}$ doped $TiO_2$ nano-powder was prepared by sol-gel method, the nature of luminescence of nano-powder was studied. The interaction of chlorpyrifos with $Eu^{3+}$ doped $TiO_2$ was studied by absorption and fluorescence spectroscopy. The results indicated the fluorescence intensity of $Eu^{3+}$ doped $TiO_2$ was quenched by chlorpyrifos and the quenching rate constant ($k_q$) was $1.24{\times}10^{11}\;L/mol{\cdot}s$ according to the Stern-Volmer equation. The dynamics of photoinduced electron transfer from chlorpyrifos to conduction band of $TiO_2$ nanoparticle was observed and the mechanism of electron transfer had been confirmed by the calculation of free energy change (${\Delta}G_{et}$) by applying Rehm-Weller equation as well as energy level diagram. A new rapid method for detection of chlorpyrifos was established according to the fluorescence intensity of $Eu^{3+}$ doped $TiO_2$ was proportional to chlorpyrifos concentration. The range of detection was $5.0{\times}10^{-10}-2.5{\times}10^{-7}mol/L$ and the election limit ($3{\sigma}$) was $3.2{\times}10^{-11}$ mol/L.

Hyperpolarized 129 NMR Study of TiO2 Nanotubes

  • Lee, Sang-Man;Lee, Soon-Chang;Mehrotra, Vandana;Kim, Hae-Jin;Lee, Hee-Cheon
    • Bulletin of the Korean Chemical Society
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    • v.33 no.2
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    • pp.511-514
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    • 2012
  • A continuous flow hyperpolarized (HP) $^{129}Xe$ NMR spectroscopy was employed for the first time to investigate $TiO_2$ nanotubes (Ti-NTs) synthesized from commercial nanoparticles with different reaction times. A single peak attributing to channels for Ti-NTs was observed for variable temperature HP $^{129}Xe$ NMR spectra. It was also noted that there is alteration in value for heat of adsorption, ${\Delta}H$ from $12.6{\pm}1.3$ to $16.4{\pm}0.4kJ/mol$ and variation in chemical shift of the xenon adsorbed in channels, ${\delta}_s$ from $120{\pm}2\sim135{\pm}9ppm$ which were closely correlated to channel length and it was shown that P25-24 Ti-NTs with longest channel is most favorite Ti-NTs for Xe adsorption.

The Synthesis of Nano-sphere Titanium-oxide and Cosmetic Applications (광반사체로 사용되는 $TiO_2$ 나노구형체의 합성과 화장품으로의 적용 연구)

  • Lee, Ji Hye;Kim, Joon Woo;Kim, Ji Man;Choung, Suk-Jin
    • Applied Chemistry for Engineering
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    • v.24 no.3
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    • pp.231-238
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    • 2013
  • In this study, the $TiO_2$ nano spheres were synthesized by Sol-gel method to give an excellent UV-blocking effect and increase waste adsorption. The pH value was adjusted to obtain a superb UV-blocking effect and adsorption capacity due to the high surface area which is the characteristics of porosity. Base treated $TiO_2$ showed outstanding characteristics. The adsorption of gycerine onto the $TiO_2$ sample using TGA resulted in a high surface area of 1.16 mg/mg. This also showed a high reflectance in the UV-A region. In order to find the optimum dispersion, inorganic powder particles were maintained their sizes as 180 nm for about 6 months. The size of particles were measured using ester oil and silicon oil. Overall, the results reveal that $TiO_2$ has an excellent capability sunscreen in the UV-A region and skin waste adsorption.